A wide number of surgical procedures employ surgical clips of a variety of configurations to provide, for example, hemostasis and occlusion of anatomical structures (i.e., tissue, blood vessels or other fluid ducts) or to secure the ends of a suture, as in place of a conventional suture knot. Often it is required to efficiently place a number of surgical clips during a single surgical procedure.
Surgical clips are commonly used to ligate, clamp, close off or otherwise occlude blood vessels in a surgical site to keep the surgical site free of blood and minimize blood loss from the patient. For example, when the surgery involves the removal of a portion of the body, such as an organ, graft vessel, tumor, or the like, that portion must be first separated from the attached vessels. In these types of procedures a vessel is ligated by action of one or more surgical clips placed at a desired location and is then severed downstream of the ligated location. In some instances, it may be desirable to place one or more clips at two adjacent locations and then sever the vessel in between the locations of the clips.
The clips are often in the form of thin, narrow, metal or polymeric U-shaped or V-shaped members that are placed over the vessel, tissue or suture material and then forced into a closed position using a clip applicator constructed for such purpose. The clips, typically constructed of metal, may be initially open and then permanently deformed into a closed or clamped configuration around the desired blood vessel or other tissue structure using an appropriate clip applicator. Examples of such clips are described in U.S. Pat. Nos. 5,201,746; 4,976,722; 4,844,066; 4,799,481; 4,449,530; and 4,146,130.
In many instances, and particularly when the clip is constructed of a material other than metal, the clip will include a latch feature to ensure that the clip remains closed with sufficient force to provide full and complete hemostasis or occlusion and to ensure that the clip will not loosen or open over time. Such latched clips are described, for example, in U.S. Pat. Nos. 5,160,339; 4,620,541, and 4,579,118.
Clips that have clamping members formed in a normally closed position are also known. Normally closed clips typically have their clamping members biased together by way of the elasticity of the material from which it is constructed. In general, to apply a clip configured in a normally closed position, the clamping members must be forced open by an appropriate clip applicator and then released to its closed position in place over the desired structure to be clamped. Normally closed clips may be formed of a continuous wire having torsion spring or tension coil as described, for example, in U.S. Pat. No. 5,593,414 or may be of a variety of other configurations such as, for example, those described in U.S. Pat. Nos. 5,695,505; 5,601,574; 5,366,458; and 4,957,500.
Whether the clip is configured in a normally closed or normally open configuration, the clip must provide sufficient clamping force to secure the structure being clamped. In the case of ligating blood vessels or the like, the clips must provide sufficient clamping force to fully close the vessel to ensure complete hemostasis. In addition, to prevent leakage or positional migration, the clips must remain tightly closed in their clamped position without any significant loosening or relaxing over time.
These requirements tend to result in the necessity for the clip to deliver a substantial amount of force to the structure to be clamped. In turn, the clip applier apparatuses for applying these clips must proportionally provide sufficiently high forces to either deform the clamp to its closed position or force the clamp to an open position for delivery. As a result, known clip appliers have been characterized by relatively complicated and bulky jaw assemblies designed to generate the high forces required to reliably and permanently apply the clips.
The complication and bulkiness associated with the clip applicators have a number of adverse effects. The added size or bulk of the clip applier adversely affects the ability of the surgeon to view the clip that is about to be applied. In many cases, the clip is almost completely obscured from view by the jaw assembly that is required to open or close the clamp. Further, excessive forces required to open or close the surgical clip must ultimately be delivered by the hand of the surgeon, often in the context of very delicate and precise surgical manipulations.
In endoscopic surgical procedures, where the clips must be delivered and applied to a surgical site through the small diametrical operating space of a relatively long cannula, these deficiencies become even more acute. Excessively large clip applicator mechanisms are inappropriate for endoscopic delivery and tend to adversely affect the endoscopic visibility of the clip placement at the surgical site. Further, in an endoscopic procedure, even small movements at the proximal end of a clip applier device may be greatly magnified at the distal end which is located a relatively large distance away at the surgical site. Accordingly, excessive forces required to apply a surgical clip tend to adversely effect the precision with which a clip may be delivered.
In view of these and other prevalent problems of known clips and clip appliers it would be desirable to have a reliable surgical clip configured for placement using only minimal force. It would be further desirable to have a surgical clip that allows improved visual access to its clamping members during placement and closure around a structure to be clamped. Further, it would be desirable to have a clip applier apparatus that can surgically apply the clips to the desired structure without substantial visual obstruction to the clamping portion of the clip. Most desirably, the clip and clip applier apparatus would operate in conjunction to allow the clip applier to be loaded with a number of clips for sequential delivery of one or more clips at a time.